Deformable medium for controlling a light stream



E. F. FISCHER July 29, 1952 DEFORMABLE MEDIUM FOR CONTROLLING A LIGHT STREAM Filed Dec. 23, 1947 1.730877%? 17 Fischer fliiorheys Patented July 29, 195 2 r DEFORIVIABLE.MEDIUM FOR CONTROLLIN a A QH STREAM isch enluri'ch,Switzerland, V r J ap lic uiirnecafibr 23, 1947, Serial No. 793,369

In Switzerland August 28, 1940 i 2. Qlaims. (01178-75) "Phis invention relates to ateleyision apparatus quired to permit small enforced deformatibns,ibut and more especially to the flatly extended medium no variation .in..'t'he: total surface to those used therein to'be deformedby the electron beam enforced-deformations a: I I A52: n r n for controlling the light stream. j v 7 V In additiomthe deformationunust'be'maintaim An arrangement of the; optical parts of such able foria definiteutimeeso that ithe contrbl or apparatus is represented in the accompanying regulation:of-thelight stream ismageneraliposdrawing, in which I represents a light source, the sib'leifor a zcertai'n rlength of time; ;For example, light rays of which are projected on to the conif it-is-a questionzof producingnn the projection denser lenses 2 and then through the diaphragm screen a,.television:pictu're:by'suitable "control of or gap 3 onto a converging. lens 4. The convergthe cathode ray and thustsuitable charge disinglens portrays, the gaps on abar 5. An objectributi'on F011 themediumr-it is clear that :in additivefianda mirror l for projecting the flight on tion to the requirement-lthat th'edeformation to the projection screen 8 arearranged in the should remainfor:arscertainitime,.-this deformafu'rther path of the ray and the formable medium tion must also completely disappear in a deter- ID is a an ed l t a trou h or co ta herfi b6- 5 minabletimeinorder'tdbeiableto recordafresh tw n t c nv rg ng l s 4 a t r The picture on the medium'.: -':In this; it is n'ota quesdefvlimetion of the medium I it takes -bra tion or the removal-of the applied chargey-for this electron b m I by 113 .1 can, as is known;==take= place, for example,- by cumulates charges n the Surface of h m u conductivity of the medium; but or the medium Thls type of dPfOTmatmFIS i f' he being in the-positionof maintaininfg'the deformaexample shown in the drawmg, 1n which I I 1nd1- tion, m e a,certalinwtime. to,,cajuse it cates the source of electrons and I2 the cathode w .di z l p a a ray effecting the deformation. VTh'e a b =d fi a rr ngfightis;in lgnu I 2,391,451; dated"; ecenib'er 25, j 4 f sequently, the projection screen remains dark. 3 ifiigfig j fg ggigfi f fulfills Now, as soon as a deformation of the medium H) 7 occurs the light rays are deflected, i. e., they are g gg g fifi g f gf fi fig g fifgg gf zgj f 5 and thus hght reaches the sistance to'the disappearancefof ithe deformation If a television picture is to be produced on the j q by h P g l h fl f g t projection screen, the vprocedure is such that hgmd hafvmg f if m 1.165.811 there is produced on the medium by a carrier- 5 satlefymgi f to herelnitfiier' frequency modulated electron beam, a charge'dis- P hqmd h t f i 'ii fncmon tribution which deforms the medium into nu- In accordance WlthTthe mventlon' be used merous lenses, disposed adjacent to one another. or there can be ?"i-" j d it n The carrier frequency, recording speed and size cell Wausas 9? m e e e nl of lens have a definite ratio, since lens size-(dis- 40 form of comma a I i a Y tance from point to point) multiplied by -icarrier t has now been w h usable i d frequency gives the recordingspeedr'By carrier h ri s .l dstaepe e used Within frequency modulated electron beam is understood (lulte defimte items r ure m t and f h 0 an electron beam in which the carrier frequency side F F m 'l ne x' l b h is superimposed on the deflection velocity and the l-lquld changgrs' i a p the superimposed frequency can be either a According to he. nv i tf h o h velocity modulation or an intensity modulation. is kept nw i t m ur nw f' In such an arrangement, the liquid should-have mqr has en ell we t i certain characteristics, since although a small which ly m l r her qu r t nts deformation could certainly be produced loy elecas have been l rtm l pp y QP d ft trical auxiliary means, this deformation would laws, especially Wh j 'pq p Q F i immediately be dissolved agaimimoreover, the enon t 511118408 O the medium a char e corree tire surface would be set in motion and thus a Sponding to a television Pmture, which charge controllable regulation of the light stream would must then, according t t e p ctu e freque cy, be impossible. Consequently, the medium is redisappear completely after the P j The characteristic values referred to above are as follows:

Electrical conductivity (K) Dielectric constant (6) Capillarity constant (a) Viscosity (k) Recording speed of the cathode ray Frequency of the carrier (to) Number of pictures per second (N) The liquid must satisfy the following equations:

10 a c m-QJV and F-Q fEN wherein the constants must lie within the following limits the constant as possessing the dimension of a conductivity. V

A satisfactory television picture, and thus an accurately controllable and determinable regulation of a light stream, can only take place when the liquid satisfies these conditions. The final product of continued distillation of mineral oil has a vapour pressure which is so low that it can be used in a high vacuum. For example, such an oil has already been marketed for many years under the name "Apiezonol (Apiezon Oil).

This oil is reasonably viscous but the viscosity is only suitable for the purpose of the present invention if it is suitably cooled. However, by addition of Canada balsam the viscosity can easily be brought to the desired value, this method of increasing the viscosity of an oil by addition of Canada balsam being known in the art. Such a mixture still possesses insuflicient electrical conductivity, but it is a familiar fact in the art that insulating liquids may be rendered conducting to any desired degree by the addition and mixing of conducting liquids. In the present case the added liquid must obviously also have a low vapour pressure and, by suitable vapour pressure measurements on known, conducting liquids, a suitable liquid can easily be found. A chemical substance suitable for this is, for example, tributyrin.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:

1. In a system for modulating a light beam in response to modulations of a sweeping beam of electrons, said modulations corresponding with N discrete television pictures per second, superposed on a carrier wave of frequency to, wherein is provided a source of said light beam, a screen, devices for projecting said light beam upon said screen, and an opaque device intermediate said source of said light beam and said screen for intercepting said light beam, the combination of a light modulating device interposed between said source of said light beam and said opaque device, said light modulating device comprising means for generating said beam of electrons, said light modulating device further comprising an extended translucent support and a translucent liquid medium disposed as a thin layer over said support, means for projecting said electron beam against said translucent liquid medium, said liquid medium being deformable in response to 4 impact by said electron beam to provide temporary light diffraction elements for difiracting said beam of light sufficiently to pass light beyond said opaque device, said liquid medium possessing physical properties satisfying the equations:

where K is electrical conductivity, 6 is dielectric constant, k is viscosity, a is capillarity constant, and c is recording speed of the electron beam, and wherein 4 X 1514 q 3 X 1Q-12 0.3 qm lfi qe and qm being constants, said liquid medium comprising essentially the final product of the continued distillation of mineral oil, admixed with a viscosity increasing agent and with an electrical conductivity increasing agent in sufficient quantities to provide the physical characteristics required by said equations, while maintaining a vapor pressure in said liquid medium sufficiently low to enable use in high vacuum.

2. A light modulating cell comprising means for generating a beam of electrons modulated in response to a carrier of frequency to modulated by picture signal having a picture repetition rate of N pictures per second, a support, a liquid medium disposed as a thin layer over said support, and means for projecting said beam of electrons against said liquid medium and sweeping said beam of electrons across said liquid medium at a rate 0, wherein said liquid medium possesses physical properties satisfying the equations:

K en-N 0t 6 fg-Qwg' where K is electrical conductivity, 5 is dielectric constant, k is viscosity, 0. is capillarity constant, and c is recording speed of the slectron beam, and wherein ERNST FRIEDRICH FISCHER.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Fischer Dec. 25, 1945 Number 

